Seems like the nadir of happiness might track when a lot of people have teenagers in the house. I wish they had adjusted for that factor, in addition to income and health.
It was funny to me to read about the people at fifty, at the peak of their carrier and with teenagers in their house. I am 36 and have both. The first one is debatable, but the second one is 15 years old. :) I hope it'll get better from now on.